1. Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus.
2. Description of the Related Art
Electrophotographic photosensitive members for use in electrophotographic apparatuses often contain an organic photoconductive substance (a charge generating substance). While an electrophotographic apparatus forms images, electrical and mechanical external forces, such as those utilized in charging, exposure, development, transfer, and cleaning, are directly applied to an electrophotographic photosensitive member of the electrophotographic apparatus. Thus, the electrophotographic photosensitive member must be resistant to such electrical and mechanical external forces. The electrophotographic photosensitive member also should have a surface that can reduce friction (increase lubricity) against a contact member (such as a cleaning blade).
In order to increase lubricity, Japanese Patent Laid-Open No. 2008-195905 and No. 2006-328416 propose a method for introducing a particular siloxane-modified polycarbonate resin (having a siloxane structure) into a surface layer of an electrophotographic photosensitive member. Japanese Patent Laid-Open No. 2009-84556 proposes a method for introducing a particular siloxane-modified polyester resin into a surface layer.
As a result of investigations, however, the present inventors found that a siloxane material and a charge transporting substance in a surface layer of an electrophotographic photosensitive member tend to induce ghosts. More specifically, a portion of an output image irradiated with light during pre-rotation tends to have a high density (a positive ghost).
When a particular siloxane-modified polycarbonate resin or siloxane-modified polyester resin disclosed in Japanese Patent Laid-Open No. 2008-195905, No. 2006-328416, and No. 2009-84556 is used, there is room for improvement in reducing occurrence of ghost images during repeated use of an electrophotographic photosensitive member.